Changing Multi Rows in Same Coumn SQLServer

lets say it in example,i had column, which its rows contain numbers increasing -10,-9,-8,-7,....-1, those rows got bugged and changed into 1,2,3,4,.....10,
that was example, the real one is over 40,000 rows, and it was -2147483629,-2147483630,-2147483631,....etc and it turned into 1000000001,1000000002,1000000003,....
how to make script that scan for 1000000001~1000000050 (for example) and make it change them into -2147483629~-2147483679 ?